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https://git.kernel.org/pub/scm/linux/kernel/git/mm/linux.git
# Conflicts:
# arch/alpha/Kconfig
# arch/arm64/mm/pageattr.c
# arch/um/Kconfig
# fs/coredump.c
# fs/xfs/libxfs/xfs_btree.c
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull VDSO updates from Thomas Gleixner:
"Updates for the VDSO subsystem:
- Ensure that the CLOCK_AUX base calculations are properly scaled
against the base timekeeper. The update function failed to take the
fractional nanosecond part into account, which results in a
rounding error.
- Cleanup and consolidate the vsyscall headers to get rid of
pointless copies all over the architectures.
- Replace a runtime conditional in the time getter function for
namespaced clocks by simple pointer arithmetic which speeds up the
read function"
* tag 'timers-vdso-2026-10-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
vdso/vsyscall: Keep the CLOCK_AUX base scaled
vdso/math64: Add and use __iter_div64_u64_rem()
vdso/math64: Use OPTIMIZER_HIDE_VAR() in __iter_div_u64_rem()
vdso/gettimeofday: Avoid runtime conditional in do_hres_timens()
vdso: Remove __ASSEMBLER__ guards from vsyscall.h
vdso: Add asm-generic/vdso/vsyscall.h
vdso: Remove unnecessary vdso/vsyscall.h includes
riscv/hwprobe: Include vdso/datapage.h
arm64/vdso: Delete asm/vdso/vsyscall.h inclusions
x86/vdso: Delete asm/vdso/vsyscall.h inclusions
sparc/vdso: Delete asm/vdso/vsyscall.h inclusion
s390/vdso: Delete asm/vdso/vsyscall.h inclusions
sparc/vdso: Move __VDSO_PAGES to asm/vdso.h
x86/vdso: Move vDSO page definitions to asm/vdso.h
vdso: Delete asm-generic/vdso/vsyscall.h
vdso/vsyscall: Define fallback time synchronization functions in vsyscall.c
vdso/getrandom: Define fallback __arch_get_vdso_u_rng_data() in getrandom.c
vdso/gettimeofday: Define fallback __arch_get_vdso_u_time_data() in gettimeofday.c
vdso: Move the kernel-side time update helpers to a new header
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__do_fast_syscall_32() fetches the user's EBP from the stack slot the
vDSO stashed it in. On 64-bit kernels it used __get_user(), as a
micro-optimization: the address is explicitly 32 bits, so it cannot be
out of range.
That optimization has turned into a pessimization. On x86-64,
get_user() checks the address with a compare and a conditional move,
while __get_user() does an lfence instead. Use get_user() on both
32-bit and 64-bit, which also removes the IS_ENABLED(CONFIG_X86_64)
special case.
This is part of getting rid of __get_user() and __put_user() entirely.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The inclusions are unnecessary, remove them.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260909-vdso-asm-generic-vsyscall-h-v1-10-63ae856cc659@linutronix.de
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The section-based vmemmap optimization infrastructure is guarded by
CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP, but it can also be used by
ZONE_DEVICE users that set dev_pagemap::vmemmap_shift. Introduce
CONFIG_VMEMMAP_OPTIMIZATION as a common config for the shared
infrastructure.
Select the new option from HUGETLB_PAGE_OPTIMIZE_VMEMMAP and from
ZONE_DEVICE when the architecture opts in to DAX vmemmap optimization, and
use it to guard the generic sparse-vmemmap state and helpers.
Link: https://lore.kernel.org/20260930140627.57431-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Qi Zheng <qi.zheng@linux.dev>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <chleroy@kernel.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Lance Yang <lance.yang@linux.dev>
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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator fixes from Jason Donenfeld:
- VMGENID memory needs to be mapped with the decrypted tag, so that
SEV-SNP machines can boot
- A fix for an initialization race in VMGENID, followed by a cleanup
- Trivial kernel doc cleanups in siphash and random.c
- A fix for a new compilation failure with recent clang on PPC and
RISC-V, due to generating an out-of-line memset in the vDSO
* tag 'random-7.3-rc6-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: vDSO: avoid call to memset() when zeroing reserved parameter
random: fix vgetrandom_opaque_params kernel-doc
random: vDSO: fix repeated word 'to' in comment
siphash: clean up kernel-doc comments
virt: vmgenid: move to using dev_set/get_drvdata
virt: vmgenid: set driver_data before registering notification handlers
virt: vmgenid: remap memory as decrypted
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After a recent change in LLVM [1], builds with the random vDSO
implementation, such as PowerPC and RISC-V, fail when checking the vDSO:
arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported
arch/riscv/kernel/vdso/vdso.so.dbg: dynamic relocations are not supported
memset() is now generated when zeroing params->reserved for some builds
because LLVM has an optimization (now run in more instances) that can
recognize at compile time when it is assigning a static value to a
contiguous area of memory and turn that into a call to memset(). Both
clang and GCC assume memset() is always available [2].
Clang has an internal fiddly hook, -max-store-memset, which we can set
to a high number, to disable generating out of line memset calls [3].
Similarly, GCC has -finline-stringops=memset to do the same [4], should
this issue ever hit future version of GCC. While these options wouldn't
make sense for normal kernel code, it is fine for the extremely limited
and intentionally compact vDSO code.
Link: https://github.com/llvm/llvm-project/commit/90cebef1411617fc3eedd359bdf00cb44b1c2439 [1]
Link: https://gcc.gnu.org/onlinedocs/gcc-16.2.0/gcc/Standards.html#index-ffreestanding [2]
Link: https://github.com/llvm/llvm-project/commit/b28eeb28bea39148738dc375e8a97072a1907e64 [3]
Link: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-finline-stringops [4]
Closes: https://github.com/ClangBuiltLinux/linux/issues/2183
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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FRED event delivery does not use the IDT, so the gate DPL check that
rejects a user INT n falls to software (Intel FRED specification [1],
section 8.3). fred_intx() rejects the same vectors as IDT delivery, but
reports a zero error code and the IP after the INT. This breaks the
signal ABI. Wine uses the error code to recognize INT 0x2d, so the
changed context turns a handled breakpoint into an access violation in
Elden Ring.
Rewind IP using the instruction length in the augmented SS and
synthesize the IDT selector error code, (vector << 3) | 2. Set RF in the
saved flags, as the CPU does for a #GP fault. Section 5.2.1 defines the
saved vector, instruction length and RF state. The supplied length
handles prefixes without reading user memory. Limit the changes to
already-rejected software interrupts, preserving the accepted INT3, INT4
and enabled INT80 paths and hardware exceptions. With IA32 emulation
disabled, INT 0x80 now reports the same #GP as the DPL 0 gate IDT
installs there. The rewound IP also stops fixup_iopl_exception() from
inspecting the byte after the INT.
Also clear the software event flag. Section 6.2.3 specifies that ERETU
with this flag and TF set traps before executing any user instruction. A
tracer that suppresses SIGSEGV and resumes with TF set expects the next
instruction to run first, as after IRET. The sigreturn path clears the
same flag for this reason in prevent_single_step_upon_eretu().
[1] Intel Flexible Return and Event Delivery (FRED) Specification,
revision 9.0 (346446-009US), sections 5.2.1, 6.2.3 and 8.3.
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/work_items/15745
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/work_items/16132
Reported-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Link: https://cdrdv2.intel.com/v1/dl/getContent/678938 # [1]
Link: https://patch.msgid.link/20260917230907.2080792-2-matthew.schwartz@linux.dev
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 entry update from Dave Hansen:
"Fix frame pointer unwinder when it encounters FRED stack frames"
* tag 'x86_entry_for_7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry/fred: Encode frame pointer on entry
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull VDSO updates from Thomas Gleixner:
- Consolidate the VDSO datastore further and provide support for
mlock_all() and prefaulting.
- Provide 32-bit legacy time related functionality only if
CONFIG_COMPAT_32BIT_TIME is enabled. The config switch exists,
but architecture code still exposes the legacy functionality even
disabled.
Clean this up by adding the missing guards and validating at build
time that the VDSO is legacy free if disabled.
- Consolidate the VDSO related config options in core and drivers,
which removes some non-sensical dependencies and quite an amount of
#ifdeffery.
- Clean up the PAGE_SIZE definition maze
* tag 'timers-vdso-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits)
random: vDSO: Drop custom PAGE_SIZE definitions
LoongArch: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery
clocksource/drivers/timer-riscv: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery
clocksource/drivers/arm_arch_timer: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery
clocksource/drivers/mips-gic-timer: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery
MIPS: csrc-r4k: Remove CONFIG_GENERIC_GETTIMEOFDAY ifdeffery
vDSO: Make clockmode constants available without CONFIG_GENERIC_GETTIMEOFDAY
kbuild: Support generated asm-headers in subdirectories
vdso: Rename HAVE_GENERIC_VDSO to VDSO_DATASTORE
vdso: Drop HAVE_GENERIC_VDSO from architecture kconfig files
vdso: Automatically select HAVE_GENERIC_VDSO if necessary
MIPS: vdso: Stop using CONFIG_HAVE_GENERIC_VDSO
vdso: Remove the dependency on HAVE_GENERIC_VDSO from ARCH_HAS_VDSO_ARCH_DATA
futex: Remove dependency on HAVE_GENERIC_VDSO from FUTEX_ROBUST_UNLOCK
vdso/gettimeofday: Verify COMPAT_32BIT_TIME interactions
sparc: vdso: Respect COMPAT_32BIT_TIME
MIPS: VDSO: Respect COMPAT_32BIT_TIME
powerpc/vdso: Respect COMPAT_32BIT_TIME
ARM: VDSO: Respect COMPAT_32BIT_TIME
arm64: vdso32: Respect COMPAT_32BIT_TIME
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull generic entry code updates from Thomas Gleixner:
- Make syscall user dispatching configurable
Not all architectures can makes use of syscall user dispatching.
Allow them to disable the feature completely.
- Consolidate stack randomization for the generic entry code and the
architectures using it.
Stack randomization on syscall entry was sprinkled throughout the
architecture specific low level entry code and in some cases at the
wrong points, e.g. before establishing state, which violates the
non-instrumentable constraints of that code.
Clean this up by integrating stack randomization into the generic
entry code helpers so that it is invoked at the earliest possible
point right after establishing state and converting all generic entry
code using architecture over.
- Clean up the syscall number handling in the generic entry code. It
works correctly for architectures which have a separate return value
storage in pt_regs, but fails to distinguish the case where user
space handed in -1 as syscall number from the case where the entry
code rejects it by returning -1 to the callers. Aside of that the
return value functionality of those interfaces is not really
intuitive.
Fix this by separating the decision to reject a syscall (user
dispatch, ptrace, seccomp ...) from the potential modification of the
syscall number through these mechanisms.
This solves most of the problems for architectures which do not have
a separate return value storage in pt_regs except for the case where
a tracepoint has a BPF script or a probe attached which overwrite
both the syscall number and the return value. But that's a problem
which cannot be solved in the generic code, that only can be
addressed by separating the storage model in the affected
architectures.
* tag 'core-entry-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
entry, treewide: Make syscall_enter_from_user_mode[_work]() indicate syscall execution
entry: Make return type of syscall_trace_enter() bool
entry: Rework trace_syscall_enter()
entry: Rework syscall_audit_enter()
syscall_user_dispatch: Introduce ARCH_SUPPORTS_SYSCALL_USER_DISPATCH
entry: Fix seccomp bypass after ptrace with TSYNC
x86/entry: Simplify the syscall number logic
x86/entry: Get rid of the sys_ni_syscall() indirection
x86/entry: Make syscall functions static
ptrace, treewide: Rename ptrace_report_syscall_entry() to ptrace_report_syscall_permit_entry()
seccomp, treewide: Rename and convert __secure_computing() to return boolean
entry: Use syscall number instead of rereading it
entry: Remove syscall_enter_from_user_mode()
x86/syscall: Use [syscall_]enter_from_user_mode_randomize_stack()
s390/syscall: Use enter_from_user_mode_randomize_stack()
riscv/syscall: Use syscall_enter_from_user_mode_randomize_stack()
powerpc/syscall: Use syscall_enter_from_user_mode_randomize_stack()
loongarch/syscall: Use syscall_enter_from_user_mode_randomize_stack()
entry: Provide [syscall_]enter_from_user_mode_randomize_stack()
randomize_kstack: Provide add_random_kstack_offset_irqsoff()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull failfs filesystem from Christian Brauner:
"Add failfs and expose a FD_FAILFS_ROOT sentinel.
This allows userspace to shed their filesystem state completely. A
process with its root or working directory in failfs must anchor every
path lookup at an explicit file descriptor. Absolute paths, absolute
symlinks and AT_FDCWD-relative lookups simply fail.
Failfs is the counterpart to nullfs. nullfs says adds a permanently
empty, immutable directory whose lookups fail with ENOENT but which
can be opened, read, stat'd and mounted upon. Failfs on the other hand
fails every operation. The root cannot be opened at all. A single
instance is mounted during early boot via kern_mount(), which makes it
logically distinct from every mount namespace.
This is accompanied by a new fchroot() system call which makes
chrooting via a file descriptor a first class concept. It's possible
to chroot into failfs as an unprivileged user provided the task has no
new privileges set"
* tag 'vfs-7.3-rc1.failfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
Documentation: add failfs documentation
selftests/filesystems: add failfs selftests
arch: hookup fchroot() system call
fs: support FD_FAILFS_ROOT in fchroot()
fs: add fchroot()
fs: support FD_FAILFS_ROOT in fchdir()
fs: add failfs
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Wire up the fchroot() system call as number 472 on (nearly) all
architectures and sync the mirrored copies of the syscall tables and
the asm-generic unistd.h under tools/.
Link: https://patch.msgid.link/20260724-work-failfs-v2-5-485dabbae185@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
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An attacker injecting interrupts while the Safe-RET mitigation executes
on machines affected by SRSO can neutralize the safe return sequence,
potentially leading to data leakage through speculative execution.
Fixup register state as if the Safe-RET sequence executed successfully
by "emulating" it, in a manner of speaking, and avoid executing a RET
instruction after returning from the interrupt.
Co-developed-by: David Kaplan <David.Kaplan@amd.com>
Signed-off-by: David Kaplan <David.Kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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execution
The return values of syscall_enter_from_user_mode[_work]() are
non-intuitive. Both functions return the syscall number which should be
invoked by the architecture specific syscall entry code. The returned
number can be:
- the unmodified syscall number which was handed in by the caller
- a modified syscall number (ptrace, seccomp, trace/probe/bpf)
That has an additional twist. If the return value is -1L then the caller is
not allowed to modify the return value as that indicates that the modifying
entity requests to abort the syscall and set the return value already. That
can obviously not be differentiated from a syscall which handed in -1 as
syscall number.
The most trivial way to deal with that is:
set_return_value(regs, -ENOSYS);
nr = syscall_enter_from_user_mode(regs, nr);
if (valid(nr))
handle_syscall(regs, nr);
That's what LOONGARCH, RISCV, and X86 do. But PowerPC and S390 do not
preset the return value, so when user space hands in -1 and there is
nothing setting the return value in the entry work code, then the syscall
is skipped but the return value is whatever random data has been in the
return value register.
Change the return values of syscall_enter_from_user_mode[_work]() to
boolean and return false, when either ptrace or seccomp request to skip the
syscall. If they return true, update the syscall number as it might have
been changed.
That results in slightly different behaviour of the architectures versus
tracing.
If the syscall tracepoint has probe/BPF attached, those might set the
syscall number to -1 and also set the return value. PowerPC and S390 will
then overwrite that value with -ENOSYS. The other architectures will just
ignore it like any other invalid syscall and use the modified one.
Originally-by: Michal Suchánek <msuchanek@suse.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Michal Suchánek <msuchanek@suse.de>
Link: https://patch.msgid.link/20260712141346.772209074@kernel.org
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Add missing ENCODE_FRAME_POINTER macro invocation into FRED_ENTER macro,
to prevent the unwinder from encountering a NULL stack frame pointer
when CONFIG_UNWINDER_FRAME_POINTER is enabled
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
Signed-off-by: David Stevens <stevensd@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://patch.msgid.link/20260424191456.2679717-12-stevensd@google.com
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Converting from int to long, back to int and then to unsigned int is
confusing at best.
None of this voodoo is required. Negative syscall numbers including -1
don't need any of this treatment and the low level ASM code already does
the sign extension to 64-bit on a 64-bit kernel.
The only point where signedness matters is the comparison against the
maximum syscall number, but that can be simplified by just using a unsigned
argument for the various syscall invocation functions.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Link: https://patch.msgid.link/20260707190254.545214398@kernel.org
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Invoking sys_ni_syscall() from a code path, which already knows that the
syscall number is invalid just to assign -ENOSYS to regs->ax is a pointless
exercise. It's even redundant as the low level entry code already has set
regs->ax to -ENOSYS on entry.
Remove the extra conditionals and the function calls.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20260707190254.493733289@kernel.org
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They are only used in the respective source files. No point in exposing
them.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Link: https://patch.msgid.link/20260707190254.438361565@kernel.org
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The return value of __secure_computing() currently uses 0 to indicate
that a system call should be allowed, and -1 to indicate that it should
be blocked/killed. This 0/-1 pattern is non-intuitive for a security
check function and makes the control flow at the call sites less readable.
Furthermore, any potential future changes to these return values would
require a high-risk, error-prone audit of all its users across different
architectures.
Sanitize this logic by converting the return type of __secure_computing()
to a proper boolean, where 'true' explicitly means 'allow' and 'false'
means 'fail/deny'.
Update all the two dozen or so call sites across the tree to align with
this new boolean semantic. No functional changes are intended, as the
callers still return -1 to the lower-level assembly entry code upon
seccomp denial.
Rename the function to __seccomp_permit_syscall() so that the purpose is
entirely clear.
[ tglx: Rename the function ]
Suggested-by: Thomas Gleixner <tglx@kernel.org>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://patch.msgid.link/20260707190254.230735780@kernel.org
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These functions integrate the stack randomization.
syscall_enter_from_user_mode_randomize_stack() has the advantage that the
randomization happens early right after enter_from_user_mode().
In both cases also the overhead of get/put_cpu_var() in
add_random_kstack_offset() is avoided.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Reviewed-by: Radu Rendec <radu@rendec.net>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
Link: https://patch.msgid.link/20260707190254.079478122@kernel.org
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If CONFIG_COMPAT_32BIT_TIME is disabled then the vDSO should not
provide any 32-bit time related functionality. This is the intended
effect of the kconfig option and also the fallback system calls would
also not be implemented.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20260702-vdso-compat_32bit_time-v3-3-db9f36d8d432@linutronix.de
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gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Remove redundant GHCB initialization guards in the SEV page state and
SVSM call paths now that the GHCB helpers handle early-boot fallback
internally
- Skip SNP initialization in the CCP driver immediately when the
preparation step fails rather than proceeding to an operation that
will certainly fail
- Abort SNP preparation and return an error when not all CPUs are
online, since the firmware enforces that every CPU enables SNP and
will fail init if not
- Simplify the VMM communication exception entry path by replacing
separate kernel and user mode macros with a single handler that
dispatches based on the current privilege level
* tag 'x86_sev_for_v7.2_rc1' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
x86/sev: Remove redundant ghcbs_initialized checks around __sev_{get,put}_ghcb()
crypto/ccp: Skip SNP_INIT if preparation fails
x86/sev: Do not initialize SNP if missing CPUs
x86/entry: Zap the #VC entry user and kernel macros
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gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Futex updates:
- Optimize futex hash bucket access patterns (Peter Zijlstra)
- Large series to address the robust futex unlock race for real, by
Thomas Gleixner:
"The robust futex unlock mechanism is racy in respect to the
clearing of the robust_list_head::list_op_pending pointer because
unlock and clearing the pointer are not atomic.
The race window is between the unlock and clearing the pending op
pointer. If the task is forced to exit in this window, exit will
access a potentially invalid pending op pointer when cleaning up
the robust list.
That happens if another task manages to unmap the object
containing the lock before the cleanup, which results in an UAF.
In the worst case this UAF can lead to memory corruption when
unrelated content has been mapped to the same address by the time
the access happens.
User space can't solve this problem without help from the kernel.
This series provides the kernel side infrastructure to help it
along:
1) Combined unlock, pointer clearing, wake-up for the
contended case
2) VDSO based unlock and pointer clearing helpers with a
fix-up function in the kernel when user space was interrupted
within the critical section.
... with help by André Almeida:
- Add a note about robust list race condition (André Almeida)
- Add self-tests for robust release operations (André Almeida)
Context analysis updates:
- Implement context analysis for 'struct rt_mutex'. (Bart Van Assche)
- Bump required Clang version to 23 (Marco Elver)
Guard infrastructure updates:
- Series to remove NULL check from unconditional guards (Dmitry
Ilvokhin)
Lockdep updates:
- Restore self-test migrate_disable() and sched_rt_mutex state on
PREEMPT_RT (Karl Mehltretter)
Membarriers updates:
- Use per-CPU mutexes for targeted commands (Aniket Gattani)
- Modernize membarrier_global_expedited with cleanup guards (Aniket
Gattani)
- Add rseq stress test for CFS throttle interactions (Aniket Gattani)
percpu-rwsems updates:
- Extract __percpu_up_read() to optimize inlining overhead (Dmitry
Ilvokhin)
Seqlocks updates:
- Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens)
Lock tracing:
- Add contended_release tracepoint to sleepable locks such as
mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry
Ilvokhin)
MAINTAINERS updates:
- MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng)
Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra,
Dmitry Ilvokhin and Peter Zijlstra"
* tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits)
locking: Add contended_release tracepoint to sleepable locks
locking/percpu-rwsem: Extract __percpu_up_read()
tracing/lock: Remove unnecessary linux/sched.h include
futex: Optimize futex hash bucket access patterns
rust: sync: completion: Mark inline complete_all and wait_for_completion
MAINTAINERS: Add RUST [SYNC] entry
cleanup: Specify nonnull argument index
selftests: futex: Add tests for robust release operations
Documentation: futex: Add a note about robust list race condition
x86/vdso: Implement __vdso_futex_robust_try_unlock()
x86/vdso: Prepare for robust futex unlock support
futex: Provide infrastructure to plug the non contended robust futex unlock race
futex: Add robust futex unlock IP range
futex: Add support for unlocking robust futexes
futex: Cleanup UAPI defines
x86: Select ARCH_MEMORY_ORDER_TSO
uaccess: Provide unsafe_atomic_store_release_user()
futex: Provide UABI defines for robust list entry modifiers
futex: Move futex related mm_struct data into a struct
futex: Make futex_mm_init() void
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux
Pull Kbuild / Kconfig updates from Nathan Chancellor:
"Kbuild:
- Remove broken module linking exclusion for BTF
- Add documentation around how offset header files work
- Include unstripped vDSO libraries in pacman packages
- Bump minimum version of LLVM for building the kernel to 17.0.1 and
clean up unnecessary workarounds
- Use a context manager in run-clang-tools
- Add dist macro value if present to release tag for RPM packages
- Detect and report truncated buf_printf() output in modpost
- Add __llvm_covfun and __llvm_covmap to section whitelist in modpost
- Support Clang's distributed ThinLTO mode
- Remove architecture specific configurations for AutoFDO and
Propeller to ease individual architecture maintenance
Kconfig:
- Add kconfig-sym-check target to look for dangling Kconfig symbol
references and invalid tristate literal values
- Harden against potential NULL pointer dereference
- Fix typo in Kconfig test comment"
* tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (31 commits)
kconfig: tests: fix typo in comment
kconfig: Remove the architecture specific config for Propeller
kconfig: Remove the architecture specific config for AutoFDO
modpost: Add __llvm_covfun and __llvm_covmap to section_white_list
kconfig: add kconfig-sym-check static checker
kbuild: Remove unnecessary 'T' modifier in cmd_ar_builtin_fixup
kbuild: distributed build support for Clang ThinLTO
kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
scripts: modpost: detect and report truncated buf_printf() output
kbuild: rpm-pkg: append %{?dist} macro to Release tag
run-clang-tools: run multiprocessing.Pool as context manager
compiler-clang.h: Drop explicit version number from "all" diagnostic macro
compiler-clang.h: Remove __cleanup -Wunused-variable workaround
kbuild: Remove check for broken scoping with clang < 17 in CC_HAS_ASM_GOTO_OUTPUT
x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags'
x86/module: Revert "Deal with GOT based stack cookie load on Clang < 17"
x86/build: Drop unnecessary '-ffreestanding' addition to KBUILD_CFLAGS
scripts/Makefile.warn: Drop -Wformat handling for clang < 16
riscv: Drop tautological condition from TOOLCHAIN_NEEDS_OLD_ISA_SPEC
riscv: Remove tautological condition from selection of ARCH_SUPPORTS_CFI
...
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When the FUTEX_ROBUST_UNLOCK mechanism is used for unlocking (PI-)futexes,
then the unlock sequence in userspace looks like this:
1) robust_list_set_op_pending(mutex);
2) robust_list_remove(mutex);
lval = gettid();
3) if (atomic_try_cmpxchg(&mutex->lock, lval, 0))
4) robust_list_clear_op_pending();
else
5) sys_futex(OP,...FUTEX_ROBUST_UNLOCK);
That still leaves a minimal race window between #3 and #4 where the mutex
could be acquired by some other task which observes that it is the last
user and:
1) unmaps the mutex memory
2) maps a different file, which ends up covering the same address
When then the original task exits before reaching #5 then the kernel robust
list handling observes the pending op entry and tries to fix up user space.
In case that the newly mapped data contains the TID of the exiting thread
at the address of the mutex/futex the kernel will set the owner died bit in
that memory and therefore corrupt unrelated data.
Provide a VDSO function which exposes the critical section window in the
VDSO symbol table. The resulting addresses are updated in the task's mm
when the VDSO is (re)map()'ed.
The core code detects when a task was interrupted within the critical
section and is about to deliver a signal. It then invokes an architecture
specific function which determines whether the pending op pointer has to be
cleared or not. The unlock assembly sequence on 64-bit is:
mov %esi,%eax // Load TID into EAX
xor %ecx,%ecx // Set ECX to 0
lock cmpxchg %ecx,(%rdi) // Try the TID -> 0 transition
.Lstart:
jnz .Lend
movq %rcx,(%rdx) // Clear list_op_pending
.Lend:
ret
So the decision can be simply based on the ZF state in regs->flags. The
pending op pointer is always in DX independent of the build mode
(32/64-bit) to make the pending op pointer retrieval uniform. The size of
the pointer is stored in the matching criticial section range struct and
the core code retrieves it from there. So the pointer retrieval function
does not have to care. It is bit-size independent:
return regs->flags & X86_EFLAGS_ZF ? regs->dx : NULL;
There are two entry points to handle the different robust list pending op
pointer size:
__vdso_futex_robust_list64_try_unlock()
__vdso_futex_robust_list32_try_unlock()
The 32-bit VDSO provides only __vdso_futex_robust_list32_try_unlock().
The 64-bit VDSO provides always __vdso_futex_robust_list64_try_unlock() and
when COMPAT is enabled also the list32 variant, which is required to
support multi-size robust list pointers used by gaming emulators.
The unlock function is inspired by an idea from Mathieu Desnoyers.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Acked-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/20260311185409.1988269-1-mathieu.desnoyers@efficios.com
Link: https://patch.msgid.link/20260602090535.883796247@kernel.org
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There will be a VDSO function to unlock non-contended robust futexes in
user space. The unlock sequence is racy vs. clearing the list_pending_op
pointer in the task's robust list head. To plug this race the kernel needs
to know the critical section window so it can clear the pointer when the
task is interrupted within that race window. The window is determined by
labels in the inline assembly.
Add these symbols to the vdso2c generator and use them in the VDSO VMA code
to update the critical section addresses in mm_struct::futex on (re)map().
The symbols are not exported to user space, but available in the debug
version of the vDSO.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.828312645@kernel.org
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It was missed that idt_do_interrupt_irqoff() gets compiled on x84_64;
this is a problem for CFI builds because it includes an unadorned
indirect call. It is however completely dead code.
Rework things to not emit this function at all.
Fixes: 0701c9e17bd9 ("x86/kvm/vmx: Move IRQ/NMI dispatch from KVM into x86 core")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260526090631.GA4149641@noisy.programming.kicks-ass.net
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Now that the minimum supported version of LLVM for building the kernel
has been raised to 17.0.1, the inclusion condition added by
3e30278e0c71 ("x86/entry/vdso32: Omit '.cfi_offset eflags' for LLVM < 16")
will always be true. Revert the change to clean up the source code.
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://patch.msgid.link/20260517-bump-minimum-supported-llvm-version-to-17-v2-13-b3b8cda46bdd@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Vishal reported that KVM unit test 'x2apic' started failing after commit
0e98eb14814e ("entry: Prepare for deferred hrtimer rearming").
The reason is that KVM/VMX is injecting interrupts while it has interrupts
disabled, for a context that will enable interrupts, this means that
regs->flags.X86_EFLAGS_IF == 0 and irqentry_exit() will not do the right
thing.
Notably, irqentry_exit() must not call hrtimer_rearm_deferred() when the return
context does not have IF set, because this will cause problems vs NMIs.
Therefore, fix up the state after the injection.
Fixes: 0e98eb14814e ("entry: Prepare for deferred hrtimer rearming")
Reported-by: "Verma, Vishal L" <vishal.l.verma@intel.com>
Suggested-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: "Verma, Vishal L" <vishal.l.verma@intel.com>
Tested-by: David Woodhouse <dwmw@amazon.co.uk>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://patch.msgid.link/20260423155936.957351833@infradead.org
Closes: https://lore.kernel.org/r/70cd3e97fbb796e2eb2ff8cd4b7614ada05a5f24.camel%40intel.com
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Move the VMX interrupt dispatch magic into the x86 core code. This
isolates KVM from the FRED/IDT decisions and reduces the amount of
EXPORT_SYMBOL_FOR_KVM().
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: "Verma, Vishal L" <vishal.l.verma@intel.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linxu.intel.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://patch.msgid.link/20260508091829.GO3126523@noisy.programming.kicks-ass.net
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In map_vdso(), if a failure occurs during the installation of the VVAR
mappings, the error path attempts to clean up previously allocated mappings
using do_munmap(). However, the cleanup for the VVAR mapping is incorrectly
using image->size (the size of the vDSO text) instead of the actual size
allocated for the VVAR area.
Replace the incorrect do_munmap() image->size parameter with the constant
VDSO_NR_PAGES * PAGE_SIZE. Ensure the unmap size exactly matches the size
used during the vdso_install_vvar_mapping() phase to provide a symmetrical
and complete teardown of the memory region.
Fixes: e93d2521b27f ("x86/vdso: Split virtual clock pages into dedicated mapping")
Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260503191609.551817-1-trintaeoitogc@gmail.com
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Drop the separate kernel and user macros in favor of calling a single #VC
C handler which multiplexes between the kernel and user #VC entry points
by looking at CS's RPL.
Zap unused DEFINE_IDTENTRY_VC while at it.
There should be no functionality change resulting from this - just code
simplification.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A. Dadhania <nikunj@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Tested-by: Nikunj A. Dadhania <nikunj@amd.com>
Link: https://patch.msgid.link/20260420164352.32129-1-bp@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "maple_tree: Replace big node with maple copy" (Liam Howlett)
Mainly prepararatory work for ongoing development but it does reduce
stack usage and is an improvement.
- "mm, swap: swap table phase III: remove swap_map" (Kairui Song)
Offers memory savings by removing the static swap_map. It also yields
some CPU savings and implements several cleanups.
- "mm: memfd_luo: preserve file seals" (Pratyush Yadav)
File seal preservation to LUO's memfd code
- "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan
Chen)
Additional userspace stats reportng to zswap
- "arch, mm: consolidate empty_zero_page" (Mike Rapoport)
Some cleanups for our handling of ZERO_PAGE() and zero_pfn
- "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu
Han)
A robustness improvement and some cleanups in the kmemleak code
- "Improve khugepaged scan logic" (Vernon Yang)
Improve khugepaged scan logic and reduce CPU consumption by
prioritizing scanning tasks that access memory frequently
- "Make KHO Stateless" (Jason Miu)
Simplify Kexec Handover by transitioning KHO from an xarray-based
metadata tracking system with serialization to a radix tree data
structure that can be passed directly to the next kernel
- "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas
Ballasi and Steven Rostedt)
Enhance vmscan's tracepointing
- "mm: arch/shstk: Common shadow stack mapping helper and
VM_NOHUGEPAGE" (Catalin Marinas)
Cleanup for the shadow stack code: remove per-arch code in favour of
a generic implementation
- "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin)
Fix a WARN() which can be emitted the KHO restores a vmalloc area
- "mm: Remove stray references to pagevec" (Tal Zussman)
Several cleanups, mainly udpating references to "struct pagevec",
which became folio_batch three years ago
- "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl
Shutsemau)
Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail
pages encode their relationship to the head page
- "mm/damon/core: improve DAMOS quota efficiency for core layer
filters" (SeongJae Park)
Improve two problematic behaviors of DAMOS that makes it less
efficient when core layer filters are used
- "mm/damon: strictly respect min_nr_regions" (SeongJae Park)
Improve DAMON usability by extending the treatment of the
min_nr_regions user-settable parameter
- "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka)
The proper fix for a previously hotfixed SMP=n issue. Code
simplifications and cleanups ensued
- "mm: cleanups around unmapping / zapping" (David Hildenbrand)
A bunch of cleanups around unmapping and zapping. Mostly
simplifications, code movements, documentation and renaming of
zapping functions
- "support batched checking of the young flag for MGLRU" (Baolin Wang)
Batched checking of the young flag for MGLRU. It's part cleanups; one
benchmark shows large performance benefits for arm64
- "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner)
memcg cleanup and robustness improvements
- "Allow order zero pages in page reporting" (Yuvraj Sakshith)
Enhance free page reporting - it is presently and undesirably order-0
pages when reporting free memory.
- "mm: vma flag tweaks" (Lorenzo Stoakes)
Cleanup work following from the recent conversion of the VMA flags to
a bitmap
- "mm/damon: add optional debugging-purpose sanity checks" (SeongJae
Park)
Add some more developer-facing debug checks into DAMON core
- "mm/damon: test and document power-of-2 min_region_sz requirement"
(SeongJae Park)
An additional DAMON kunit test and makes some adjustments to the
addr_unit parameter handling
- "mm/damon/core: make passed_sample_intervals comparisons
overflow-safe" (SeongJae Park)
Fix a hard-to-hit time overflow issue in DAMON core
- "mm/damon: improve/fixup/update ratio calculation, test and
documentation" (SeongJae Park)
A batch of misc/minor improvements and fixups for DAMON
- "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David
Hildenbrand)
Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code
movement was required.
- "zram: recompression cleanups and tweaks" (Sergey Senozhatsky)
A somewhat random mix of fixups, recompression cleanups and
improvements in the zram code
- "mm/damon: support multiple goal-based quota tuning algorithms"
(SeongJae Park)
Extend DAMOS quotas goal auto-tuning to support multiple tuning
algorithms that users can select
- "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao)
Fix the khugpaged sysfs handling so we no longer spam the logs with
reams of junk when starting/stopping khugepaged
- "mm: improve map count checks" (Lorenzo Stoakes)
Provide some cleanups and slight fixes in the mremap, mmap and vma
code
- "mm/damon: support addr_unit on default monitoring targets for
modules" (SeongJae Park)
Extend the use of DAMON core's addr_unit tunable
- "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache)
Cleanups to khugepaged and is a base for Nico's planned khugepaged
mTHP support
- "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand)
Code movement and cleanups in the memhotplug and sparsemem code
- "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup
CONFIG_MIGRATION" (David Hildenbrand)
Rationalize some memhotplug Kconfig support
- "change young flag check functions to return bool" (Baolin Wang)
Cleanups to change all young flag check functions to return bool
- "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh
Law and SeongJae Park)
Fix a few potential DAMON bugs
- "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo
Stoakes)
Convert a lot of the existing use of the legacy vm_flags_t data type
to the new vma_flags_t type which replaces it. Mainly in the vma
code.
- "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes)
Expand the mmap_prepare functionality, which is intended to replace
the deprecated f_op->mmap hook which has been the source of bugs and
security issues for some time. Cleanups, documentation, extension of
mmap_prepare into filesystem drivers
- "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes)
Simplify and clean up zap_huge_pmd(). Additional cleanups around
vm_normal_folio_pmd() and the softleaf functionality are performed.
* tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm: fix deferred split queue races during migration
mm/khugepaged: fix issue with tracking lock
mm/huge_memory: add and use has_deposited_pgtable()
mm/huge_memory: add and use normal_or_softleaf_folio_pmd()
mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio()
mm/huge_memory: separate out the folio part of zap_huge_pmd()
mm/huge_memory: use mm instead of tlb->mm
mm/huge_memory: remove unnecessary sanity checks
mm/huge_memory: deduplicate zap deposited table call
mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE()
mm/huge_memory: add a common exit path to zap_huge_pmd()
mm/huge_memory: handle buggy PMD entry in zap_huge_pmd()
mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc
mm/huge: avoid big else branch in zap_huge_pmd()
mm/huge_memory: simplify vma_is_specal_huge()
mm: on remap assert that input range within the proposed VMA
mm: add mmap_action_map_kernel_pages[_full]()
uio: replace deprecated mmap hook with mmap_prepare in uio_info
drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare
mm: allow handling of stacked mmap_prepare hooks in more drivers
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Dave Hansen:
- Complete LASS enabling: deal with vsyscall and EFI
The existing Linear Address Space Separation (LASS) support punted
on support for common EFI and vsyscall configs. Complete the
implementation by supporting EFI and vsyscall=xonly.
- Clean up CPUID usage in newer Intel "avs" audio driver and update the
x86-cpuid-db file
* tag 'x86_cpu_for_7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tools/x86/kcpuid: Update bitfields to x86-cpuid-db v3.0
ASoC: Intel: avs: Include CPUID header at file scope
ASoC: Intel: avs: Check maximum valid CPUID leaf
x86/cpu: Remove LASS restriction on vsyscall emulation
x86/vsyscall: Disable LASS if vsyscall mode is set to EMULATE
x86/vsyscall: Restore vsyscall=xonly mode under LASS
x86/traps: Consolidate user fixups in the #GP handler
x86/vsyscall: Reorganize the page fault emulation code
x86/cpu: Remove LASS restriction on EFI
x86/efi: Disable LASS while executing runtime services
x86/cpu: Defer LASS enabling until userspace comes up
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 vdso updates from Ingo Molnar:
"vdso cleanups by Thomas Weißschuh:
- Clean up remnants of VDSO32_NOTE_MASK
- Drop pointless #ifdeffery in vvar_vclock_fault()"
* tag 'x86-vdso-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Drop pointless #ifdeffery in vvar_vclock_fault()
x86/vdso: Clean up remnants of VDSO32_NOTE_MASK
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull vdso updates from Thomas Gleixner:
- Make the handling of compat functions consistent and more robust
- Rework the underlying data store so that it is dynamically allocated,
which allows the conversion of the last holdout SPARC64 to the
generic VDSO implementation
- Rework the SPARC64 VDSO to utilize the generic implementation
- Mop up the left overs of the non-generic VDSO support in the core
code
- Expand the VDSO selftest and make them more robust
- Allow time namespaces to be enabled independently of the generic VDSO
support, which was not possible before due to SPARC64 not using it
- Various cleanups and improvements in the related code
* tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
timens: Use task_lock guard in timens_get*()
timens: Use mutex guard in proc_timens_set_offset()
timens: Simplify some calls to put_time_ns()
timens: Add a __free() wrapper for put_time_ns()
timens: Remove dependency on the vDSO
vdso/timens: Move functions to new file
selftests: vDSO: vdso_test_correctness: Add a test for time()
selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c
selftests: vDSO: vdso_test_correctness: Handle different tv_usec types
selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks
selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks
Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers"
random: vDSO: Remove ifdeffery
random: vDSO: Trim vDSO includes
vdso/datapage: Trim down unnecessary includes
vdso/datapage: Remove inclusion of gettimeofday.h
vdso/helpers: Explicitly include vdso/processor.h
vdso/gettimeofday: Add explicit includes
random: vDSO: Add explicit includes
MIPS: vdso: Explicitly include asm/vdso/vdso.h
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
- randomize_kstack: Improve implementation across arches (Ryan Roberts)
- lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test
- refcount: Remove unused __signed_wrap function annotations
* tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test
refcount: Remove unused __signed_wrap function annotations
randomize_kstack: Unify random source across arches
randomize_kstack: Maintain kstack_offset per task
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The 32-bit VDSO build on x86_64 uses fake_32bit_build.h to undefine
various kernel configuration options that are not suitable for the VDSO
context or may cause build issues when including kernel headers.
Undefine CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP in fake_32bit_build.h to
prepare for change in HugeTLB Vmemmap Optimization.
Link: https://lkml.kernel.org/r/20260227194302.274384-12-kas@kernel.org
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Sparse complains rightfully when CONFIG_PARAVIRT_CLOCK and
CONFIG_HYPERV_TIMER are both not set:
arch/x86/entry/vdso/vma.c:94:9: warning: switch with no cases
The #ifdeffery is not actually necessary as the compiler can optimize away
the branches already if these config options are not set.
Remove the #ifdeffery to make the code simpler and Sparse happy.
Closes: https://lore.kernel.org/lkml/20260117215542.405790227@kernel.org/
Reported-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://patch.msgid.link/20260331-vdso-x86-ifdef-v1-1-6be9a58b1e7e@linutronix.de
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Previously different architectures were using random sources of
differing strength and cost to decide the random kstack offset. A number
of architectures (loongarch, powerpc, s390, x86) were using their
timestamp counter, at whatever the frequency happened to be. Other
arches (arm64, riscv) were using entropy from the crng via
get_random_u16().
There have been concerns that in some cases the timestamp counters may
be too weak, because they can be easily guessed or influenced by user
space. And get_random_u16() has been shown to be too costly for the
level of protection kstack offset randomization provides.
So let's use a common, architecture-agnostic source of entropy; a
per-cpu prng, seeded at boot-time from the crng. This has a few
benefits:
- We can remove choose_random_kstack_offset(); That was only there to
try to make the timestamp counter value a bit harder to influence
from user space [*].
- The architecture code is simplified. All it has to do now is call
add_random_kstack_offset() in the syscall path.
- The strength of the randomness can be reasoned about independently
of the architecture.
- Arches previously using get_random_u16() now have much faster
syscall paths, see below results.
[*] Additionally, this gets rid of some redundant work on s390 and x86.
Before this patch, those architectures called
choose_random_kstack_offset() under arch_exit_to_user_mode_prepare(),
which is also called for exception returns to userspace which were *not*
syscalls (e.g. regular interrupts). Getting rid of
choose_random_kstack_offset() avoids a small amount of redundant work
for the non-syscall cases.
In some configurations, add_random_kstack_offset() will now call
instrumentable code, so for a couple of arches, I have moved the call a
bit later to the first point where instrumentation is allowed. This
doesn't impact the efficacy of the mechanism.
There have been some claims that a prng may be less strong than the
timestamp counter if not regularly reseeded. But the prng has a period
of about 2^113. So as long as the prng state remains secret, it should
not be possible to guess. If the prng state can be accessed, we have
bigger problems.
Additionally, we are only consuming 6 bits to randomize the stack, so
there are only 64 possible random offsets. I assert that it would be
trivial for an attacker to brute force by repeating their attack and
waiting for the random stack offset to be the desired one. The prng
approach seems entirely proportional to this level of protection.
Performance data are provided below. The baseline is v6.18 with rndstack
on for each respective arch. (I)/(R) indicate statistically significant
improvement/regression. arm64 platform is AWS Graviton3 (m7g.metal).
x86_64 platform is AWS Sapphire Rapids (m7i.24xlarge):
+-----------------+--------------+---------------+---------------+
| Benchmark | Result Class | per-cpu-prng | per-cpu-prng |
| | | arm64 (metal) | x86_64 (VM) |
+=================+==============+===============+===============+
| syscall/getpid | mean (ns) | (I) -9.50% | (I) -17.65% |
| | p99 (ns) | (I) -59.24% | (I) -24.41% |
| | p99.9 (ns) | (I) -59.52% | (I) -28.52% |
+-----------------+--------------+---------------+---------------+
| syscall/getppid | mean (ns) | (I) -9.52% | (I) -19.24% |
| | p99 (ns) | (I) -59.25% | (I) -25.03% |
| | p99.9 (ns) | (I) -59.50% | (I) -28.17% |
+-----------------+--------------+---------------+---------------+
| syscall/invalid | mean (ns) | (I) -10.31% | (I) -18.56% |
| | p99 (ns) | (I) -60.79% | (I) -20.06% |
| | p99.9 (ns) | (I) -61.04% | (I) -25.04% |
+-----------------+--------------+---------------+---------------+
I tested an earlier version of this change on x86 bare metal and it
showed a smaller but still significant improvement. The bare metal
system wasn't available this time around so testing was done in a VM
instance. I'm guessing the cost of rdtsc is higher for VMs.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-3-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
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FRED-enabled SEV-(ES,SNP) guests fail to boot due to the following issues
in the early boot sequence:
* FRED does not have a #VC exception handler in the dispatch logic
* Early FRED #VC exceptions attempt to use uninitialized per-CPU GHCBs
instead of boot_ghcb
Add X86_TRAP_VC case to fred_hwexc() with a new exc_vmm_communication()
function that provides the unified entry point FRED requires, dispatching
to existing user/kernel handlers based on privilege level. The function is
already declared via DECLARE_IDTENTRY_VC().
Fix early GHCB access by falling back to boot_ghcb in
__sev_{get,put}_ghcb() when per-CPU GHCBs are not yet initialized.
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org> # 6.12+
Link: https://patch.msgid.link/20260318075654.1792916-4-nikunj@amd.com
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Commit in Fixes forgot to convert one include path to be relative to the
kernel source directory after adding latter to flags-y.
Fix it.
[ bp: Rewrite commit message. ]
Fixes: 693c819fedcd ("x86/entry/vdso: Refactor the vdso build")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20260307174406.1808981-1-vladimir.oltean@nxp.com
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The EMULATE mode of vsyscall maps the vsyscall page with a high kernel
address directly into user address space. Reading the vsyscall page in
EMULATE mode would cause LASS to trigger a #GP.
Fixing the LASS violation in EMULATE mode would require complex
instruction decoding because the resulting #GP does include the
necessary error information, and the vsyscall address is not
readily available in the RIP.
The EMULATE mode has been deprecated since 2022 and can only be enabled
using the command line parameter vsyscall=emulate. See commit
bf00745e7791 ("x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATE") for
details. At this point, no one is expected to be using this insecure
mode. The rare usages that need it obviously do not care about security.
Disable LASS when EMULATE mode is requested to avoid breaking legacy
user software. Also, update the vsyscall documentation to reflect this.
LASS will only be supported if vsyscall mode is set to XONLY (default)
or NONE.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://patch.msgid.link/20260309181029.398498-5-sohil.mehta@intel.com
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Background
==========
The vsyscall page is located in the high/kernel part of the address
space. Prior to LASS, a vsyscall page access from userspace would always
generate a #PF. The kernel emulates the accesses in the #PF handler and
returns the appropriate values to userspace.
Vsyscall emulation has two modes of operation, specified by the
vsyscall={xonly, emulate} kernel command line option. The vsyscall page
behaves as execute-only in XONLY mode or read-execute in EMULATE mode.
XONLY mode is the default and the only one expected to be commonly used.
The EMULATE mode has been deprecated since 2022 and is considered
insecure.
With LASS, a vsyscall page access triggers a #GP instead of a #PF.
Currently, LASS is only enabled when all vsyscall modes are disabled.
LASS with XONLY mode
====================
Now add support for LASS specifically with XONLY vsyscall emulation. For
XONLY mode, all that is needed is the faulting RIP, which is trivially
available regardless of the type of fault. Reuse the #PF emulation code
during the #GP when the fault address points to the vsyscall page.
As multiple fault handlers will now be using the emulation code, add a
sanity check to ensure that the fault truly happened in 64-bit user
mode.
LASS with EMULATE mode
======================
Supporting vsyscall=emulate with LASS is much harder because the #GP
doesn't provide enough error information (such as PFEC and CR2 as in
case of a #PF). So, complex instruction decoding would be required to
emulate this mode in the #GP handler.
This isn't worth the effort as remaining users of EMULATE mode can be
reasonably assumed to be niche users, who are already trading off
security for compatibility. LASS and vsyscall=emulate will be kept
mutually exclusive for simplicity.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://patch.msgid.link/20260309181029.398498-4-sohil.mehta@intel.com
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With LASS, vsyscall page accesses will cause a #GP instead of a #PF.
Separate out the core vsyscall emulation code from the #PF specific
handling in preparation for the upcoming #GP emulation.
No functional change intended.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Link: https://patch.msgid.link/20260309181029.398498-2-sohil.mehta@intel.com
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When building the compat vDSO the CHECKFLAGS from the 64-bit kernel
are used. These are combined with the 32-bit CFLAGS. This confuses
sparse, producing false-positive warnings or potentially missing
real issues.
Manually override the CHECKFLAGS for the compat vDSO with the correct
32-bit configuration.
Reported-by: Sun Jian <sun.jian.kdev@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20260302-vdso-compat-checkflags-v2-1-78e55baa58ba@linutronix.de
Closes: https://lore.kernel.org/lkml/20260114084529.1676356-1-sun.jian.kdev@gmail.com/
Closes: https://lore.kernel.org/lkml/20260117215542.342638347@kernel.org/
Closes: https://lore.kernel.org/r/202602111941.PIhubgrb-lkp@intel.com/
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The unwinder code in libgcc has a long standing bug which causes it to
fail to pick up the signal frame CFI flag. This is a generic bug
across all platforms.
It affects the __kernel_sigreturn and __kernel_rt_sigreturn vdso entry
points on i386. The x86-64 kernel doesn't provide a sigreturn stub,
and so there is no kernel-provided code that is affected on x86-64.
libgcc does have a legacy fallback path which happens to work as long
as the bytes immediately before each of the sigreturn functions fall
outside any function. This patch adds a nop before the ALIGN to each
of the sigreturn stubs to ensure that this is, indeed, the case.
The rest of the patch is just a comment which documents the invariants
that need to be maintained for this legacy path to work correctly.
This is a manifest bug: in the current vdso, __kernel_vsyscall is a
multiple of 16 bytes long and thus __kernel_sigreturn does not have
any padding in front of it.
Closes: https://lore.kernel.org/lkml/f3412cc3e8f66d1853cc9d572c0f2fab076872b1.camel@xry111.site
Fixes: 884961618ee5 ("x86/entry/vdso32: Remove open-coded DWARF in sigreturn.S")
Reported-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124050
Link: https://patch.msgid.link/20260227010308.310342-1-hpa@zytor.com
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array_index_nospec() is no use if the result gets spilled to the stack, as
it makes the believed safe-under-speculation value subject to memory
predictions.
For all practical purposes, this means array_index_nospec() must be used in
the expression that accesses the array.
As the code currently stands, it's the wrong side of irqentry_enter(), and
'index' is put into %ebp across the function call.
Remove the index variable and reposition array_index_nospec(), so it's
calculated immediately before the array access.
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260106131504.679932-1-andrew.cooper3@citrix.com
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Commit 93d73005bff4 ("x86/entry/vdso: Rename vdso_image_* to
vdso*_image") updated the vdso .gitignore file with the new filenames,
which is certainly not incorrect.
However, while adding new generated names is obviously the right thing
to do, you should *not* immediately remove the old filenames from the
.gitignore file when things move around or get renamed, because people
still have those old generated files in their build trees - and they
haven't suddenly become valid files to commit to the repository just
because they were moved or renamed.
While it's mostly just a slight visual nuisance for 'git status' that
can be fixed up with a clean build tree, it can become more serious than
that: see for example commit 04a3389b3535 ("Remove stale generated
'genheaders' file").
That commit removed up a stale generated file that had been carelessly
committed by a kernel developer because it wasn't properly ignored any
more and thus showed up as a new file in their tree.
Fixes: 93d73005bff4 ("x86/entry/vdso: Rename vdso_image_* to vdso*_image")
Cc: Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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